. >>> and the footloose first lady. why michelle obama is going viral tonight. >>> and good evening. i'm dan harris. we'll get to david muir in iran in just a moment. >>> but we're going to start with the breaking news out of florida. a treacherous finale to a race at the daytona international speedway today. look at the video. cars colliding, getting tossed around like toys. pieces of them flying over a fence, injuring at least a dozen people, many of them fans. abc's linzie janis is on the story. >> reporter: one driver sparked a dramatic crash on the daytona track. >> and contact!